Electric-arc lamp.



119,691,549.' 9 Pafented 1an. 2|,- |992. 9 s. H. Johnson. l

ELECTRIC ARC LAMP.

(Application led July 29,- 1901.)

3 Sheets-Sheet 'I.

(no M0991.)

1H: Noam Pnrens oo.. FHorauTno., wAsmNnroN. D. c

No.` 69|,549. Patented 1an. 2|, |902.

s. HfJnHNsoN.

ELECTRIC ARC LAMP.

(Application led July 29, 1901.)

(No Model.) 3 Sheets-Sheet. 2.

No. 69|,549. Patented 1an. 2|, |902. s. H. Jameson.

ELEcTm Anc LAMP.

(Appxietion med .hay 2x9,v 1901.)

(No Model.) 3 Sheets-Sheet 3.

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xUNITED STATES PATENT .OFFTCEQ SAMUEL HENRY JOHNSON, OF S'FRATFORD, ENGLAND.

ELECTRIC-ARC LAlVlP' SPECIFICATION formingpart of Letters Patent No. 691,549, dated January 21, 1902.

' Application filed July 29, 1901. Serial No. 70,128. (No model-l To @ZZ whom, t 'may concern.: v

Be it known that I, SAMUEL HENRY' JOHN- SON, a subject of the King of England, residing at Stratford, county of Essex, England, have invented certain new and useful Improvements inV or Relating to Electric-Arc Lalnps, (for which I have made applicationA kind; but such lamps have hitherto been un-v successful for various reasons, among which may be mentioned the absence of any arrangement whereby a regular or step-by-step feeding of the movable carbon could be obtained, the frequent stoppage of the arcl through the carbons not .coming into contact automatically after the current had been broken, and the fact that the lamps were generally designed so that the feeding-point corresponded to the striking rather than to the working position of the carbons.

In arc-lamps according to this invention, asis generally the case in lamps of the type mentioned, the thermo expansive strip is connected to a spring-controlled lever operating a slip-clutch encircling the upper carbon or carbon-holder. The object of this invention, however, is to introduce features which obviate the disadvantages above mentioned and make the lamp efiicient and reliable without rendering it unduly complicated.

In order that the feeding action shall beA nection isprovrided between theauxiliary clutch and the spring-controlled lever, so that movement of the latter due to the contraction ing-arm.

to their striking positions, a tripping-lever I or the like is provided, which automatically comes into action after the arc has been struck.

In order that my invention may be clearly understood and readily carried into effect, I shall proceed to describethe same fully, with reference to the accompanying drawings, in which f Figure 1 is a side elevation ofalamp ittcd with clutch mechanism according to this invention. Fig. 2 is a side'elevation of the lamp-bracket with a portion of the support- Figs. 3, 4, and 5 arelside elevations of the clutch mechanism in different positions assumed when the lamp is at rest and working.

Like letters indicate like 'parts throughout the drawings.

In constructing the improved apparatus for regulating the are a thermo-expansive strip A is connected to a lever B, controlled by a spring B, operating a slip-clutch B2, encircling the upper carbon or carbon-holder C. I further provide an auxiliary clutch D2, encircling the upper carbon Oabove the ordinary clutch B2. The upper clutch D2 is suspended from a lever D, having a counterweight D and providedwithv stops on each side E E', so that the lever D has a limited motion proportional .to the space through which the upper carbon O is moved .at eachr step of the feed, p

The connecting-link between the lower clutchB2 and the end of the spring-controlled lever B consists of a pin F, passing freely through a hole in the clutch and provided with a head to prevent its withdrawal.

A projection D8 is fitted to the upper clutch f i D2, so that the movement' of the spring-controlled lever B due to the expansion of the strip A when the current increases trips and releases the' upper clutch D, then pushes it into a new and higher position on the upper carbon, limited to the preadjusted feed by the stop E, as shown in dotted lines in Figi.

In order that the feedingpoint of the lamp shall correspond to the working position of the carbons, a tripping-lever Gr is provided, having a projection G', which automatically IOO swings beneath the lower clutch B2 after the arc has been struck. This lever Gis pivoted at G2 and carried on the clutch-guide standard H, attached to the casting forming the upper-carbon guide. Thelever G is also provided with a inger G3, which is engaged by the lever B as it falls when the current is cut off, Fig. 5.

The tailpiece Dl of the upper clutch D2 is provided with a link J, through which the lever B passes, in order that the movement of the latter due to the contraction of the strip A when the current ceases may trip the upper clutch D2, Fig. 5.

The lever B, which is actuated by the strip A, is pivoted at B3 and is provided with a vise A', which grips one end of the strip A. The terminal of the lead K which conveys the current to the upper carbon C is attached, by means of the binding-screw L, to the other end of the thermo-expansive strip A, and an adjusting-screw M is also provided for the strip A. The initial position o' the lever B can be adjusted by means of the screw M', which engages the end of the spring B'. In-

sulators N support the strip where necessary,

and insulation N' is also provided at other points. Contact between the lever B and upper carbon C is made by the short flexible connection O and carbon-contact P. The other terminal is connected through the vertical rod Q and casting Q', forming the lower-carbon holder'of the lamp.

The globe R of the lamp is rendered easily and safely removable by placing asbestos washers R2 in the globe-rests R', the lower rest being in form of a collar supported on a coiled spring R2.

To explain the operation of the mechanism above described in regulating the feed of the lamp, it will be advantageous to describe what takes place from the time of switching on the current to the lamp. When the mechanism is at rest before the current is turned on, as illustrated in Fig. 3, the lower clutch B2 will be resting on the clutch-rest H', and the link F will have passed through the hole in the clutch B2 for some distance below the clutchrestH'. Whenthelamp-circuitiscompleted, the expansion-lever B will begin to rise, owing to the expansion of the strip A, permitting the spring B' to contract and raise the leverB and the suspension-link F. The mechanism is arranged so that when the lamp is cold the link F protrudes through the clutch B2, and hence when the current is turned on the first momentary action of the expansion of the strip A is to take up what may be termed the slack in the link F before the clutch B2 is tilted to grip the carbon C, as shown by the dotted position in Fig. 3. It

will be readily understood that this slack provides a margin which is sufficient to insure that however long the are may be when the current is cut o the clutch B2 will reach its tripping-point and allow the upper carbon C to slip right through it into contact with the lower one. The expansion continuing, the spring B' continues to raise the lever B, carrying with it the clutch B2 and lifting the upper carbon C, thereby striking the are. As the current continues the strip A further expands and the lever B continues to rise, during which time the clutch B2 pushes the pivoted lever G out of its way until the end of the clutch B2 comes above the trip-table G of the trip-lever G, which then automatically swings beneath the lower clutch B2, ready to trip it when required, Fig. 1. Normally the projection G' on the tri ppin g-lever G trips the lower clutch B2 for feeding the upper carbon C, so that feeding takes place at a point where the distance between the carbons is approximately the length of the arc when struck and separated to the normal Working position. The carbons gradually burn away, and the length of the arc becomes increased, producing a greater resistance, gradually diminishing the current passing through the thermoexpansive strip A, with the result that the temperature is reduced, and owing to the consequent contraction of the strip the lever B is lowered, carrying with it the upper carbon and clutch B2 until'the latter is tripped on the trip-table G' of the tripping-lever, G. The upper carbon C is thus allowed Ato pass through the clutch B2, but is immediately seized by the upper clutch D2, so that the carbon C in dropping pulls down the upper lever D until it meets the limiting-stop E', which prevents the further descent of the carbon. slight shortening ofthe are increases the eurrent, and the thermo-expansive strip A expands, bringing the lower clutch B2 into its operative position, and then the auxiliary clutch D2 is tripped by the end of the springcontrolled lever B coming into contact with the projection D3, which causes the upper clutch D2 to take the new position higher up on the carbon, ready for the next step of the feed, as illustrated in Fig. 4. When the current is broken and the expansive strip A contracts, the spring-controlled lever B, operated thereby, is brought into contact with the nger Gson the pivoted tripping-lever G, so that the projection G' is removed from under the lower clutch B2, andthe latter thus falls onto the clutch-rest H' in the position' itoccupied before the arc was struck, as shown in Fig. 5. The carbon C is seized by the upper clutch D2and falls therewith until the leverD meets the stop E', as in the ordinary process of feeding above described; but the current having ceased the stripA continues to contract, so that the carbon C is suspended in the upper clutch until the lever B touches the bottom of the link J, which trips the upper clutch D2, allowing the carbons to come together, Fig. 5.

The tripping-level' G might be omitted; but in that case it would be necessary to depend on the clutch-rest H for tripping the clutch B2 when the feedis required. A very considerable shortening of the arc and consequent reduction in the amount of light would ICO The

IIO

then take place before the lower clutch B2 could return to the rest H' to be tripped thereon and let 'the upper carbon C pass. There would consequently be a very considerable variation in the amount of light emitted by the lamp, corresponding to the distance to which the carbons might be separated.

, The clutch-gears have been described and illustrated as applied to an upper carbon; but theyconld of course beapplied to any movable carbon.

In the construction illustrated in the accompanying drawings the thermo-expansive strip Ais so placed that it is notiniinenced by the heat of the arc, an obvious advantage when it is remembered that the action of the lamp depends upon the temperatnrepof the strip. The strip-A is placed horizontally, being supported bythe insulators A' upon a bracket A2 and arm A3, extending, say, from a' wall, the

arm VA3 carrying at its end'r the other portions' of the lamp. y s

Resistance or choke coils forreducing the intensity-'of the current necessary for thebest working of the arc would have to be employed with this lamp in the same way as is generally the case. These are not shown in the tripping said clutch and limited motion.

3. In an arc-lamp the combination of a pivoted lever the movement ot which is controlled by the current, a main slip-clutch on the movable carbon having a non-rigid' conlever, a rest for tripping drawings, as they do not form any part of the Y invention.

In some cases a series of brackets holding lamps can be placed'aronnd a central tube, the expansion-strips for all the lamps being placed vertically; but it is to be understood that the invention is not confined to the particular construction mentioned and that anyv alterations in detail maybe made to suitparticularcircu instances. For example, the lever B, acted upon by the expansive strip A, may becontrolled by a counterweightinstead of bya spring, or, again, the trip-lever G may be spring-controlled instead of being arranged to swing by gravity into its-position. -What 1 claim as my invention, and desire to secure by Letters Patent, is

1. In an arc-lamprthe combination of-'means controlled by the current for regulating the carbons, a main slip-clutch on the movable carbon, a rest for disen gagin g the main clutch at the minimum limit of its range', a second slip-clutch encircling the movable carbon' vand means for tilting andtrippin g said clutch and allowing'it onlya limited motion.

2. In an arc-lamp the combination of apivoted lever the xmovement of which is controlledby the current, a main slip-clutch on the movable carbon having a non-rigid connection with the lever-,a rest fordisengaging the main clutch at the minimum limit of its range, a second slip clutch encircling the movable carbon and means for tilting and nection with the range, a .second movable carbon, means for tilting 'and tripping said clutch and allowing it only a limited e motion and means for moving t-he second at the maximum limit of its range. A 4.: In an arc-lamp the combination of a pivoted lever the movement Vot whichis conthe movable carbon` having a non-rigid connection with the leyer,a restfor tripping the main clutch atthe minimum limit ot its range, a second slip-clutch encirclingv the movable carbon, means for tilting and tripping said clutch and allowing it only a .limited motion, means for moving the-second clutch on the movable carbon when the lever is at the maximum limit of itsv range and means for tripping the second clutch as the lever falls to lthe' minimum limit of its range when the current is cut off. L

5. In an arc-lain p the combination of a pivtrolled by the current, a main slip-clutch on the movable carbon having a non-'rigid connecallowing it only a# tion with Athe' lever, a rest for tripping the main 'clutch at the minimum limit of its'range,a -secallowing it only alim'ited motiorV4 means for moving the second clutch on the movable carbon when the lever is at the maximum limit of its range,- means for tripping the second clutch as the lever falls to the minimum limit of its range when the currentis cut off anda pivote'd tripping-lever adapted to engage the main clutch when the carbons exceed their normal working distance apart and adapted. to be pnt out of action by the lever when the current is cut ott.

(i. In an arc-lamp the combination of a pivotedclever the movement of which is contr'o'lled by the current, a main slip-clutch on tion-with the lever, a rest for tripping the main clutch at -its lowest position and apivoted tripping-lever adapted to engage the main clutch when lthe carbons exceed their normal working distance apart and adapted to be put out of action by the lever when. thc current is cut oit. 1

7. In an arc-lamp the combination of a thermo-expansive strip forminga partjof the circuit, a vpivoted lever connected to one 'end of said strip, a spring adapted to raise the lever when-thestrip expands, a main vslipclutch on the upper carbon connepted to the lever, a rest on which the main clutch trips when at its lowest position, a second slipclutch and normally tilted by a counter; weightedipivoted lever and stops to limit the motion of the said lever.

thermo-expansive strip forming a part of the circuit, a pivoted lever connected to one end the main clutch at the minimum limit of itsl slip-clutch encircling the clutch on the movable carbon when the leverv is i trolled by thecurrent, a main slip-clutchonv `otedlever the movement ot" which` is con ond sli p-clutch encircling the movable carbon, means for tilting and tripping said clutch and clutch encircling the carbon above the mainl ICO -IIO

the upper carbon having a non-rigid connec.-

. 8. In an arc-lamp the combination of a l of said strip, a spring adapted to raise the lever when the strip expands, a main slipclutch on the upper lever by a non-rigid link, a rest on which the main clutch trips when at its lowest position, a second slipclutch 'encircling the carbon above the main clutch and normally tilted bya counterweighted pivoted lever and stopsl to limit the motion of said lever.

9. In an arc-lamp the combination of a thermo-expansive strip forming a part of the circuit, a pivoted lever connected to one end of said strip, a spring adapted to raise the lever when the strip expands, a main slipclutch on the, upper carbon connected to the lever by a non-rigid link, a rest on which the l main clutch trips when at its lowest position,

' ver when the strip expands, a main slipaclntch on the upper carbon Aconnected to the lever by a non-rigid link, a rest on which the main clutch trips when at its lowest position, a second slip-clutch encircling the carbon above the main clutch and normally tilted by a counterweighted pivoted lever, stops to limit the motion of said lever,'a projection on the second clutch engaging with the spring-con-l trolled lever when in its highest position so as to trip the second clutch and a link on the tailpiece of the second clutch engaging with a spring-controlled lever when the current is cut 0E so as to trip the second clutch.

1l. In an arc-lamp the combination of a thermo-expansive strip forming a part of the circuit a pivoted lever connected to oneend carbon connected to the.

the motion of said lever, a projection on the second clutch engaging with the spring-controlled lever when in its highest position so as to trip the second clutch, a linkon the tailpiece of the second clutch engaging with the spring-controlled lever when the current is cut off so as to trip the second clutch, a pivoted tripping-lever havinga projection adapted to engage the main clutch when the carbons exceed theirA normal working distance apart and a finger on the tripping-lever engaging with the spring-controlled lever when the current is cut olf to put the tripping-1ever out of action.

12. In an arc-lamp the combination of a thermo-expansive strip forming a part of the circuit, a pivoted lever connected to one end of said strip,a spring adapted to raise the 1e- Ver when the strip expands,a main slip-clutch on the upper carbon connected to the lever by a non-rigid link, a rest on which the main clutch trips when at its lowest position, a pivoted tripping-lever having a projection adapted to engage the main clutch when the carbons exceed their normal working distance apart and a finger on the tripping-lever engaging with the spriugcontrol1ed lever when the current is cut off to put the trippin`glever out of action.

In testimony whereof I have signed my naine to this specification in the presence of' two subscribing witnesses.

SAMUEL HENRY JOHNSON.

Witnesses: l

WALTERJ. SKERTEN, G. F. WARREN. 

